increases the size of individual node. With the size increases, it will be slightly harder to find a suitable spot for permanent placement.
Aside multi sensing, wireless sensor network solution available on the market nowadays usually employs different wireless protocols, such as, Wi-Fi or ZigBee.
Each protocols has their own advantages but they consume more power compared to a transmitter that uses sub 1 GHz Radio Frequency RF to transmit data. Beside
higher power consumption, these wireless protocols require extra module to be installed or a bigger size microcontroller to be integrated into the system. This space
consuming feature is not needed if the user intends to use the system only in a small area.
Besides all that, there is not much development in the field of wireless sensor network that uses sub 1 GHz RF as its wireless protocol. Last but not least, wireless
sensor network customised for specific uses only is not that common in today‟s market.
1.5 Project Objective
The goal of this project is to design a wireless sensor node to monitor vibration level. This provides a wireless and a more time efficient monitoring method
to monitor machine health. Besides, this project aims to build a wireless sensor node for a more specific use that is both cost effective and low power. In short, the
objectives are as follow:
- To design a wireless sensor node for vibration level monitoring - To build a small, cost effective and low power monitoring system
consisting of MCU, RF receiver and accelerometer.
1.6 Significant of Project
The novelty of this project lies here in the wireless communication part, by using a fairly new microcontroller from Microchip Technology Inc. with the model
name PIC 12LF1840T39A. This particular microcontroller has a fully integrated Radio Frequency RF transmitter in it. The operating frequency of this controller
ranges only from 310 MHz up till 915 MHz [2]. Operating frequency of this range are usually used in remote keypad, this project will investigate the possible use of
this miniature RF integrated MCU as a sensor node to monitor vibration level.
With its integrated RF transmitter, an even smaller design of sensor node is now possible, effectively shrinking the space occupied by the node. Besides reducing
space, a smaller design means lesser parts, and this in turn reduces manufacturing cost and maintenance fee of this sensor node.
The significant of this project also lies in the capability for it to be scalable, and sustainable. The RF band used in this project is license free and common enough
to be easily integrated into other projects. Besides, with lesser modules involved, it consumes a lot less power and hence, can sustain longer with battery cell alone.
1.7 Scope
This WSN project involves only a pair of nodes for the purpose of monitoring vibration level. The pair of nodes consists of a sensor node transmitter node and a
receiver node. The pair of nodes communicate through Radio Frequency RF wave.
The testing ground planned for this project is the university‟s laboratory. Whereas the vibration source set for this project will be the vibration generator
available in the laboratory. The shaker‟s frequency and amplitude can be tuned to provide a clear picture of the reliability of the microcontroller in acquiring the data.
Vibration level monitoring system can be applied into many field, for this project, only the application in the field of machine health monitoring will be
considered. With only one year being allocated for this project, only a few aspects of the project are focused on.
First and foremost, the coding of the microcontroller is one of the main focus since this microcontroller is fairly new and not much examples were found. The
design of the circuit inside the sensor node is also one of the focus throughout the year long project. To effectively shrink down the size of the sensor node,
optimization of the circuit and better placement of components is required. This project also focused on the reliability of the data transmitted by the sensor node. The
output signal is closely observed to ensure the signal transmitted by the sensor node is reliable.
Since the signal strength and vibration frequency is not the focus of this project, therefore, the range of transmission of the sensor node is not looked into and
the transmitter only transmits to the receiver that is 5m away. Whereas the range of vibration frequency to be monitored is set to around 5 Hz up to 100 Hz. A small DC
battery is used to power up the sensor node whereas the receiver node will get its power from laptop through USB cable.
The sensor node built in this project is set to monitor only vibration level coming from one type of source. Due to time constraint, this project monitors only
one source of fixed artificial vibration generated by vibration generator, instead of random vibration level from multiple source overlapping each other.
1.8 Thesis Outline
